Machine for pre-shaping shoe parts

ABSTRACT

Two electrically non-conductive bands are movably mounted on a machine for pre-shaping shoe parts. Electrically conductive layers are provided between the two bands - the bands and the layers both being flexible. A source of high frequency electrical energy is connected to the conductive layers and to a conductive portion of a rigid form in the shape of a heel last member. A gripping jaw arrangement is provided which stretches the upper leather of the shoe over the heel last member - a thermoplastic heel stiffening or counter being heated by a high frequency heating when the upper leather has been stretched over the heel last member and the two bands are moved into the region of the heel last member.

United States atent 1 [111 3,775,796 Schindler et a]. Dec. 4, 1973 [54] MACHINE FOR PRE-SHAPING SHOE 3,039,288 6/1962 Torre et al I 12/543 3,105,250 10/1963 Kamborian et a]. 12/54.3

[30] Foreign Application Priority Data Sept. 8, 1971 Germany ..P 21 44 904.7 flexible- A Source 0f high frequency electrical energy is connected to the conductive layers and to a conduc- 52 US. Cl. 12/543 Ponio" Of form in the Shape, a heel last 51 Int. Cl. A43d 11/00 member- A gripping amhgemem is Pmvided 58 Field of Search 12154.3 53.5 8.1 which Stretches the "PPer leather 0f the 12/82 143 heel last member a thermoplastic heel stiffening or counter being heated by a high frequency heating [56] References Cited when the .upper leather has been stretched over the heel last member and the two bands are moved into UNITED STATES PATENTS the region of the heel last member. 3,545,023 12/1970 Foss eta] 12/543 1 2,983,934 5/1961 Bertrand 12/543 15 Claims, 5 Drawing Figures I f) /-:l': I i 2 5 m1 111! ||||1 1 I a I 'm I I 0 2 6/ l 1 6 II 6 e i I I PARTS Inventors: Herbert Schindler, Wagenstrasse 38,

Pirmasens; Gerhard Winter, Pirminiusstrasse 2, Hauenstein, both of Germany Filed: Sept. 5, 1972 Appl. No.2 286,585

Primary ExaminerPatrick D. Lawson AttorneyAbraham Friedman et a1.

ABSTRACT Two electrically non-conductive bands are movably mounted on a machine for pre-shaping shoe parts. Electrically conductive layers are provided between the two bands the bands and the layers both being PATENTEU DEC 4 1975 SREE" 2 0F 2 1 MACHINE FOR IRE-SHAIING SHOE PARTS BACKGROUND OF THE INVENTION This invention relates to a machine for heating and pre-shaping a thermoplastic stiffening or counter in the heel portion of a shoe upper with the aid of highfrequency means.

It is already known to heat a heel last member by means of a resistance heating arrangement. In such a device, the band which encloses the stiffening is exposed to the heat as well.

Thermoplastic materials are known in the art for the fabrication of toe-caps and the like. These materials make possible the use of high-frequency techniques which soften such thermoplastic components of the shoe upper prior to their initial shaping. Such a technique offers an important advantage in that the heat applied does not have to be conducted through the upper leather to reach the toe-cap or stiffening; instead, the heat is produced in the thermoplastic member itself by dielectric heating.

However, when using high-frequency energy, difficulties are encountered in that an electricallyconductive element in the form of a strip must be placed around the heel last member so accurately that the distance between the strip and the upper material is uniform at all points. The conductive element must thus adapt to the shape of the heel portion of the last with the upper stretched thereover. I

A further difficulty relates to the problem of finding the proper distance between the electrical conductor and the thermoplastic member to be softened for preshaping.

SUMMARY OF THE INVENTION To overcome the above disadvantages, it is an object of the present invention to provide an improvement in pre-shaping machines whichdoes not have the disadvantages of similar kn'own machines.

Another object of the present invention is to provide such an improvement which is simple in construction and economical to manufacture.

It is still another object of the present invention to provide an improvement as above described which does not require time-consuming pre-adjustments.

It is a further object ot provide an improvement of the type under discussion which does not require one of the conductive elements to be exactly configurated to a predetermined shape as was the case in previous machines.

It is still a further object to provide a high-frequency pre-shaping machine which is easy to use.

Accordingly, the present invention, for a combination for shaping frequency heat deformable materials, comprises a rigid form means for deforming the heat deformable material into a predetermined shape when the material is press-fitted in a heated and softened state against said form means. Said form means has at least one portion which is made from electrically conductive material. Flexible band means are provided which is displaceable with respect to said form means. Said flexible band means comprises at least one elongated band of electrically non-conductive material, and a conductive metal layer extending along said elongated band. Both said layer and said band are so configurated so as to be flexible. Connecting means are provided for connecting a source of high frequency electrical energy to said conductive portion and to said conductive metal layer when said flexible band means has moved to a position to press-fit the deformable material against said form means.

The structure of said band means, including said conductive layer, based on the invention has yielded very good results in actual operation. It ensures uniform heating of the entire stiffening member.

More specifically, the advantage of the structure based on the invention has been achieved by providing at least one conductive layer between two layers or bands of Teflon. The flexible band or strip can comprise a plurality of layers of different materials of which at least one material is electrically conductive. The strip or band built up from these layers is shaped approximately to conform to the outline of the heel portion of a last. The electrically-conductive layer can be I provided in the form of a foil or simply evaporated onto one or both Teflon layers. Instead of Teflon, use can be made, of course, of any other suitable dielectric material.

Another advantageous structure has the conductive foil in the form of individual strips arranged transversely on the upper band of the dielectric material and longitudinally on the lower band, or vice versa. Adjacent strips arranged to slightly overlap ensure satisfactory resilience of the entire structure and offer no resistance to deformation.

Experience has shown that sparking is readily produced at the edges of the conductive band with the result that both the metal insert structure and the plastic band itself is destroyed. According to another feature of theinvention, sparking is prevented by applying a thin film of non-conductive. material in a strip-like configuration along the edges of the metal foil.

BRIEF DESCRIPTION OF THE DRAWINGS With the above and additional objects and advantages in view, as will hereinafter appear, this invention comprises the devices, combinations and arrangements of parts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment in which: I

FIG. 1 is a front elevational view of the machine in accordance with the present invention;

FIG. 2 is a section along line I I of FIG. 1;

FIG. 3 is a section along line II II of FIG. 2, showing a top view on the clamping jaw arrangement;

FIG. 4 is a cross-section through the heel band, and

FIG. 5 is a top view of the inner side of the two outer portions of the band.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An upright frame member 1 carries a cylinder 2 whose piston rod 3 supports a base-plate 4. A baseplate 4 carries side-plates 6 which are journalled therein at support points 5.

An elongated flexible band in the form of a heel-band 7 is accommodated at the lower ends 6' of side-plate 6.

Heel-band 7 includes Teflon bands 7' and 7 Two additional layers 8 and 8 of an electrically-conductive material are disposed between bands 7' and 7". Optionally, only one conductive layer may be provided. The electrically-conductive layers are preferably composed of a plurality of overlapping metallic strips in a configuration resembling fish-scales. Alternatively,

bands 7 and 7" can be rigidly connected to layers 8 and 8.

To ensure against sparking, the edges of the metal layer or layers carry strips 23 of a non-conductive material bonded thereto.

The space defined by heel-band 7 and side-plates 6 can remain free. Alternatively, the space can be filled with a resilient material 9. This increases the biasing force exerted by heel-band 7 when the latter is lowered.

The entire moveable unit executes a rectilinear movement, being guided by a rod 10 which moves in a keyway 11.

The upper leather (not shown) is stretched over a heel last member 12. The heel last member 12 preferably matches the original last as closely as possible. The

- heel last member 12 is anchored to the upright frame member 1 by means of an isolating support element 13. Connecting means, in the form of a cam 14 which trips a limit switch 15, controls the high-frequency current supplied by a source of energy (not shown). The highfrequency current is supplied via metal strip conductors (not shown) the electrical circuit being conventional.

Holding and stretching means for the vamp portion of the upper leather is accommodated below the heel last member 12.

Two gripping jaws 16 (FIG. 3) are urged against a block 19 by means of levers 17 accommodated between gripping jaws 16 and block 19.

The gripping jaw arrangement can be guided upwards and downwards along guide means 20 with the aid of an actuation cylinder 21 in order to bring the shoe upper into firm abutment against the heel last member 12 with its heel portion. The movement of all cylinders or their pistons is governed by conventional valves known in the art (not shown). Suitable electrical circuitry, of any conventional type, cooperates with the valve system.

Heel last member 12 and heel band 7 are connected to a high-frequency generator in an opposite polar arrangement, so that a high-frequency field is formed between the metal layer 8 (8') of the heel band 7 and the metal heel last member 12. The high-frequency field generates heat which causes the softening of the thermoplastic material of the stiffening or counter.

MODE OF OPERATION With the machine at rest, the heel band 7 is in the position shown in FIG. 1. Gripping jaws 16 are at a certain distance from block 19.

The upper leather, with the counter inserted, is stretched manually with its heel portion over heel last member 12. The vamp portion of the upper leather is inserted between gripping jaws 16 and block 19; and a foot-operated switch (not shown) is actuated. In response thereto, gripping jaws l6, driven by cylinder 18, close, whereupon the entire gripping jaw arrangement, driven by cylinder 21, moves downward. As a result, the upper leather is pulled over heel last member 12 so that the heel portion thereof is tightly stretched thereover.

Cylinder 2 then moves the entire heel-band device downward towards heel last member 12 and firmly urges the heel portion of the upper leather against heel last member 12. Shortly before the end of this movement, cam 14 trips switch '15 which governs the flow of the high-frequency current. The high-frequency heat- 4 ing cycle is preferably controlled automatically, whereupon heel-band 7 and gripping jaws 16 return to their respective initial positions at the end of the cycle.

All the novel features provided in the machine are to be understood as being within the scope of the invention. The preferred embodiment of the invention described hereinbefore is given by way of example only; protection is sought for all possible combinations of the inventive features.

What is claimed is:

1. In a shaping machine, particularly for shaping frequency heat deformable material such as a thermoplastic heel portion of a shoe upper, a combination comprising rigid form means for deforming the heat deformable material into a predetermined shape when the material is press-fitted in a heated and softened state against said form means, said form means having at least a portion made from an electrically conductive material; flexible band means being displaceable with respect to said form means, said flexible band means comprising at least one elongated band of electrically non-conductive material, and a conductive metal layer extending along said elongated band, both said layer and said band being so configurated so as to be flexible, said conductive metal layer including a plurality of adjacent individual metallic strips; and connecting means for connecting a source of high frequency electrical energy to said conductive portion and to said conductive metal layer when said flexible band means has moved to a position to press'fit the deformable material against said form means.

2. A combination as defined in claim 1, wherein said metallic strips are arranged so that adjacent strips slightly overlap each other.

3. A combination as defined in claim 1, wherein two flexible bands are provided each having an inner surface facing the other band, said conductive metal layer being joined to one of said inner surfaces.

4. A combination as defined in claim 2, wherein said conductive metal layer is bonded to said one inner surface.

5. A combination as defined in claim 1, wherein said rigid form means comprises a heel last member.

6. A combination as defined in claim 1, wherein each of said metallic strips is individually connected to said elongated band.

7. A combination as defined in claim 1, wherein said conductive metal layer defines at least one edge, and further comprising non-conductive means positioned across said edge for retarding sparking once the source of electrical energy is connected.

8. A combination as defined in claim 7, wherein said non-conductive means comprises a strip of a nonconductive material of a relatively narrow width compared to that of said conductive metal layer.

9. A combination as defined inclaim 1, further including stretching means for stretching said deformable material located intermediate said rigid form means and said flexible band means, whereby stretching of the flexible band means press-fits the heat deformable material against said rigid form means.

10. A combination as defined in claim 9, wherein said deformable material comprises the upper leather of a shoe, and wherein said stretching means comprises a gripping jaw arrangement displaceable relative to said rigid form means; and activating means for displacing said jaw arrangement with respect to said rigid form.

means so as to tightly stretch the upper leather on said rigid form means.

11. A combination as defined in claim 1, wherein said flexible band means is configurated to substantially conform to the shape of said rigid form means.

12. In a shaping machine, particularly for shaping frequency heat deformable material such as a thermoplastic heel portion of a shoe upper, a combination com prising rigid form means for deforming the heat deformable material into a predetermined shape when the material is press-fitted in a heated and softened state against said form means, said form means having at least a portion made from an electrically conductive material; flexible band means being displaceable with respect to said form means, said flexible band means comprising two elongated bands of electrically nonconductive material with each having an inner surface facing the other band, and two conductive metal layers with each extending along another one of said inner surfaces of said elongated bands, both said layers and said bands being so configurated so as to be flexible;

and connecting means for connecting a source of high frequency electrical energy to said conductive-portion and to said conductive metal layers when said flexible band means has moved to a position to press-fit the deformable material against said form means.

13. A combination as defined in claim 12, wherein at least one of said conductive metal layers comprises a thin film evaporation layer deposited on an associated one of said elongated bands.

14. A combination as defined in claim 12, wherein each metal layer comprises a plurality of adjacent individual metallic strips arranged so that adjacent strips slightly overlap each other, the metallic strips of one layer being angularly displaced by an angle of up to relative to the metallic strips of the other layer.

15. A combination as defined in claim 14, wherein said strips of said one layer are oriented transversely to the direction of said bands while said strips of said other layer are oriented substantially parallel to the direction of said bands. 

1. In a shaping machine, particularly for shaping frequency heat deformable material such as a thermoplastic heel portion of a shoe upper, a combination comprising rigid form means for deforming the heat deformable material into a predetermined shape when the material is press-fitted in a heated and softened state against said form means, said form means having at least a portion made from an electrically conductive material; flexible band means being displaceable with respect to said form means, said flexible band means comprising at least one elongated band of electrically non-Conductive material, and a conductive metal layer extending along said elongated band, both said layer and said band being so configurated so as to be flexible, said conductive metal layer including a plurality of adjacent individual metallic strips; and connecting means for connecting a source of high frequency electrical energy to said conductive portion and to said conductive metal layer when said flexible band means has moved to a position to press-fit the deformable material against said form means.
 2. A combination as defined in claim 1, wherein said metallic strips are arranged so that adjacent strips slightly overlap each other.
 3. A combination as defined in claim 1, wherein two flexible bands are provided each having an inner surface facing the other band, said conductive metal layer being joined to one of said inner surfaces.
 4. A combination as defined in claim 2, wherein said conductive metal layer is bonded to said one inner surface.
 5. A combination as defined in claim 1, wherein said rigid form means comprises a heel last member.
 6. A combination as defined in claim 1, wherein each of said metallic strips is individually connected to said elongated band.
 7. A combination as defined in claim 1, wherein said conductive metal layer defines at least one edge, and further comprising non-conductive means positioned across said edge for retarding sparking once the source of electrical energy is connected.
 8. A combination as defined in claim 7, wherein said non-conductive means comprises a strip of a non-conductive material of a relatively narrow width compared to that of said conductive metal layer.
 9. A combination as defined in claim 1, further including stretching means for stretching said deformable material located intermediate said rigid form means and said flexible band means, whereby stretching of the flexible band means press-fits the heat deformable material against said rigid form means.
 10. A combination as defined in claim 9, wherein said deformable material comprises the upper leather of a shoe, and wherein said stretching means comprises a gripping jaw arrangement displaceable relative to said rigid form means; and activating means for displacing said jaw arrangement with respect to said rigid form means so as to tightly stretch the upper leather on said rigid form means.
 11. A combination as defined in claim 1, wherein said flexible band means is configurated to substantially conform to the shape of said rigid form means.
 12. In a shaping machine, particularly for shaping frequency heat deformable material such as a thermoplastic heel portion of a shoe upper, a combination comprising rigid form means for deforming the heat deformable material into a predetermined shape when the material is press-fitted in a heated and softened state against said form means, said form means having at least a portion made from an electrically conductive material; flexible band means being displaceable with respect to said form means, said flexible band means comprising two elongated bands of electrically non-conductive material with each having an inner surface facing the other band, and two conductive metal layers with each extending along another one of said inner surfaces of said elongated bands, both said layers and said bands being so configurated so as to be flexible; and connecting means for connecting a source of high frequency electrical energy to said conductive portion and to said conductive metal layers when said flexible band means has moved to a position to press-fit the deformable material against said form means.
 13. A combination as defined in claim 12, wherein at least one of said conductive metal layers comprises a thin film evaporation layer deposited on an associated one of said elongated bands.
 14. A combination as defined in claim 12, wherein each metal layer comprises a plurality of adjacent individual metallic strips arranged so that adjacent strips slightly overlap each other, the metallic strips Of one layer being angularly displaced by an angle of up to 90* relative to the metallic strips of the other layer.
 15. A combination as defined in claim 14, wherein said strips of said one layer are oriented transversely to the direction of said bands while said strips of said other layer are oriented substantially parallel to the direction of said bands. 